This invention relates to an internal combustion engine encapsulated in a soundproof manner, particularly for use in automotive vehicles. The engine has an oil pan which is sealingly secured to the engine block along substantially horizontal mounting faces.
An internal combustion engine of the above-outlined type is known and disclosed, for example, in German Laid-Open Application (Offenlegungsschrift) No. 2,403,254. In the arrangement described therein the capsule is open downwardly and thus the oil pan of the engine projects beyond the capsule through the opening into the path of the air stream generated by the motion of the vehicle. An encapsulation designed in this manner is advantageous regarding the cooling of the oil pan and its contents; such an advantage is, however, acquired by introducing a serious drawback, namely a downward escape of a substantial proportion of the sound energy emanating from the internal combustion engine.
Further, as disclosed, for example, in German Laid-Open Application (Offenlegungschrift) No. 2,411,490, sound insulated, encapsulated internal combustion engines are known which do not have the above-discussed disadvantage since underneath the internal combustion engine there is provide a lid-like component forming part of the capsule. Such structures, however, have the disadvantage that a separate additional air flow within the capsule has to be provided to ensure the required cooling of the oil.